A bioserogroup of marine vibrios possessing somatic antigen factors in common with Vibrio cholerae O1

A bioserogroup of halophilic vibrios, tentatively labelled bioserogroup 1875, strongly agglutinated by O1 antiserum of Vibrio cholerae is described. Cross‐agglutination and agglutinin‐absorption tests showed that these vibrios had antigens identical with the Ogawa and Inaba factors of V. cholerae O1, although they possessed their own specific antigen distinctive from the A factor that is the specific major antigen of the latter species. In addition, quantitative antigen variation similar to that of the Ogawa‐to‐Inaba type with V. cholerae O1 was recognized in this halophilic group. They were isolated from estuarine water and are considered to inhabit coastal aquatic environments. Phenotypically, however, this group is not identifiable with any of the species already recognized in the genus Vibrio .